Over several years I have chronographed all three of the major's FBI load, Federal, Remington and Winchester, all in 2 different 2" S&W revolvers. Different days, different temperature and different guns, but all 3 loads were amazingly close to each other. Here are the results:
9/28/2008 80 degrees W-W 158 LSWCHP +P 821 FPS Mod 12-1
3/22/2010 50 degrees Fed 158 LSWCHP +P 821 FPS Mod 12-3
(To Compare: Same load, same day 6" 10-4, 945 FPS and 6 1/2" Outdoorsman" 929 FPS)
11/30/2014 40 degrees R-P 158 LSWCHP +P, 811 FPS Model 10-5
My results, my guns different conditions. I was really surprised that these were so consistent. I rarely have shot many of these loads at the same time as they are simply too difficult to find! Usually only 5-10 rounds at a time. Not an adequate "Statistical sample", but good enough for what I wanted to know! The only time I have shot different barrel lengths was on 3/22/2010 as noted above.
Coincidentally, this afternoon returning from shooting I stopped at the Lehi, UT Cabela's. They had 2 boxes of the new Remington HTP load, so I bought a box to chronograph, which I will try to get to in the next week or so. This will be fired in the same guns as noted above, or more likely just the 10-5 the older R-P was fired in.
A short remark about +P, at least these loads. In case anyone doubts that there is a performance gain with +P ammunition, consider this. I have chronographed factory .158 gr. LRN factory loads from both Remington and W-W that pre-date the introduction of the +P standard. With the single exception of the R-P FBI load above, every one of these samples was faster from the various 2" barrels than any sample of the standard pressure 158 LRN "Police Service" loads was when fired from a 6" barrel". There was a significant difference! Here are the results:
W-W 158 LRN, 6"Highway Patrolmen, 770 FPS
Same load,6" 1948 K-38 Masterpiece, 733 FPS
R-P 158 LRN, 2 1/8" M-640-1, 683 FPS
W-W 158 LRN, 6 1/2" "Outdoorsman", 819 FPS (This was the only sample that was faster then the various "FBI Loads" fired in a 2" barrel, except for the 811 FPS R-P test above, and only by 8 FPS! Hardly significant!
If you are interested I have 14 other trials of W-W and R-P 158 LRN loads in barrels from 2" to 7 1/2". Claimed velocity was 855 FPS on the box(es), but of these 14 tests 800 FPS was exceeded only once, 805 FPS, in any of 8 different guns. This was from a 5" 1948 M&P that was 85 FPS faster than my 7 1/2" Colt Officer's Model Target. Average velocities for mostly 12 round samples ranged from 671 FPS to 805 FPS. FWIW, the OMT is consistently slow!!!
What I am trying to say, if you don't understand on your own, is that the FBI +P load from all makers significantly exceeds 6" plus barrel performance for standard pressure loads for the same bullet weight, even when fired from a 2" barrel!!!! If that doesn't convince you that there is a performance advantage with +P loads, even fired from a 2" barrel, then you are one of those people whose "Mind is made up and will not be confused by facts"!
